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Alternator Problem? Assistance needed


acdbox

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No M is mega (millions of) ohms. You are possibly measuring you skin resistance! K is kilo or thousands of ohms. You want the range at the opposite end from M, as Tony mentions it's often a 200 ohms range.

 

Anyway I'm struggling to make sense of what you are reporting, maybe you should try another meter or find someone who is more familiar with using them?

Edited by nicknorman
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No M is mega (millions of) ohms. You are possibly measuring you skin resistance! K is kilo or thousands of ohms. You want the range at the opposite end from M, as Tony mentions it's often a 200 ohms range.

 

Anyway I'm struggling to make sense of what you are reporting, maybe you should try another meter or find someone who is more familiar with using them?

 

or maybe post a photo of the meter. It sounds like an auto-ranging one because all the ones in a typical boaters budget range have a 200 ohm scale and then more positions for the k Ohms and M ohms.

 

This may not be the best meter for someone new to meter use. If you look at the screen when set to auto you may see a little k or M along the bottom or top to show what range it has set it self to.

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Thanks that helps. I'd say the meter is defective since it is showing 137.6 ohms and presuming the probe in the photo is the one plugged into the meter, since it is not connected to anything the resistance should be infinite. Did you say if you'd replaced the meter's battery?

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Yes - battery or faulty meter but more likely battery. It is a sort of auto-ranging meter.

 

The reading as shown is 137.6 Ohms.

The k or M I said may be along the top or bottom is probably on teh left so with auto there you just read the Omega on the right. Tis will probably change to V or A as volts or amps are selected.

 

When you want to measure Volts on the 12V parts of the boat make sure you use the V with the parallel solid and dotted line associated with it. That means DC. The V with the wavy line is for AC.

 

I would advise you to never use it to read amps. The maximum it can read is 10 amps and it is far too easy to burn the amps part out when changing from reading amps to any other unit. In any case the critical circuits that require the current checking far exceed 10 amps.

 

The diode symbol with the dot and "curved brackets" is the diode and continuity checker. When continuity checking just listen for a beep that maens you have continuity. Ignore any actual readings I would suggest that you do not use it to try to check a diode because you need the proper procedure and then the numbers you get can be confusing.

 

Thanks for the photo, now we can see what you are struggling with. Best advice is to change the meter batteries every year even though it seem to be working.


Someone suggested that in the thread. Haven't gotten around to it year but shall do it as a matter of priority

 

Again, not trying to have a pop at you but taking the two threads together you do seem to sometimes ignore advice. This does not help us to help you. I know you did not explicitly say that you had changed the battery but when you came back with readings I for one assume that you had dealt with the battery issue.

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Resistance reading on a cheap multimeter is never going to be massively accurate, but it doesn't need to be if its just to find continuity or not. BUT thinking logically, its VERY easy to do a sanity check:

 

1. With the probes put together, it should read near to 0 ohms. My £5 meter reads 0.6 ohms

2. With the probes apart (ie in air), it should read pretty much infinite ohms. My meter shows a figure 1 on the left (with no other figures shown), well to the left of wherever the decimal point is (depending on the scale chosen) so it won't be confused with a numerical reading.

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Resistance reading on a cheap multimeter is never going to be massively accurate, but it doesn't need to be if its just to find continuity or not. BUT thinking logically, its VERY easy to do a sanity check:

 

1. With the probes put together, it should read near to 0 ohms. My £5 meter reads 0.6 ohms

2. With the probes apart (ie in air), it should read pretty much infinite ohms. My meter shows a figure 1 on the left (with no other figures shown), well to the left of wherever the decimal point is (depending on the scale chosen) so it won't be confused with a numerical reading.

 

I agree it should not be confused but I can asure you that it id very common for it to be so confused, especially by users who have just started out with meters.

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I agree it should not be confused but I can asure you that it id very common for it to be so confused, especially by users who have just started out with meters.

Yup, it's a shame they don't just display "range" or similar to indicate out of range.

 

Tony

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Hi WotEver,

The battery probably has had it without a proper charge, though before I put a new bat in id like to resolve the alternator issue to prevent it happening again.

I may not have been clear in previous post, apologies.

The alternator has a connection problem... When a continuity test is put between the new connection made to the alternators regulator and the alternators casing it's showing there's a connection, as I understand it there shouldn't be a connection there. I've double/triple checked the new connection is not touching the casing in any way but it still shows a connection.

 

Hope that makes a bit better sense?

I am surprised the instructions warn against continuity between the connection to the -ve brush for the external reg. It's normal and correct for the regulator to connect the -ve brush (and therefore the added connection) to ground.

Not much interested in using any more time on thinking about this job unless I can finally get some answer as to what the score is with the split charge system.

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